{"id":282054,"date":"2016-09-20T02:00:00","date_gmt":"2016-09-19T23:00:00","guid":{"rendered":"http:\/\/www.fyysika.ee\/?guid=a3d0ebd8941225510a91d8ecc134670a"},"modified":"2016-09-20T02:00:00","modified_gmt":"2016-09-19T23:00:00","slug":"zero-mass-limit-of-a-dirac-spinor-with-general-spin-orientation","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=282054","title":{"rendered":"Zero-mass limit of a Dirac spinor with general spin orientation"},"content":{"rendered":"<p>The helicity eigenstates that describe fermions with a special spin orientation (parallel or<br \/>\nantiparallel to the direction of momentum) provide a considerable simplification in calculations.<br \/>\nHence, it is generally preferred to use the helicity basis during calculations in relativistic<br \/>\nquantum mechanics or the quantum field theory. Possibly for the above reason, Dirac spinors<br \/>\ndescribing a general spin orientation have been ignored in many textbooks. Although the helicity<br \/>\neigenstates give an almost complete understanding of the behavior of the free Dirac solutions, the<br \/>\nzero-mass limit is one of its exceptions. The zero-mass behavior of the free spinor with general<br \/>\nspin orientation and its relation with chirality eigenstates has been skipped in textbooks and hence<br \/>\nit deserves a clear, detailed investigation. In this paper we obtain the free Dirac spinors<br \/>\ndescribing a general spin orientation and examine their zero-mass limit. We also briefly discuss<br \/>\nsome of the implications of this&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The helicity eigenstates that describe fermions with a special spin orientation (parallel or<br \/>\nantiparallel to the direction of momentum) provide a considerable simplification in calculations.<br \/>\nHence, it is generally preferred to use the helicity basis &#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[178],"tags":[],"class_list":{"0":"post-282054","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rss-fuusikaharidus","7":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/282054","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=282054"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/282054\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=282054"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=282054"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=282054"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}